Dial indicator



Sept. 3, 1935. J G; s sso 2,013,176

DIAL INDICATOR Filed Oct. 8, 1934 Invqnior eiallws- 613L850 Patented Sept. 3, 1935 --James SissonyAthol, Mass assignor to The L. S. StarrettGompany, Athol, ,Mass, a corporation of Massachusetts Application October 8, 1934, Serial No. 747,403

3 Claims. -(c1. 116-129) My-present invention relates to certainimprovements'in adjustabledial indicators and particularly to such indicatorconstructions as include ljocking -mechanism "for the bezel ring. Such locks havefbeen'produced heretofore in a great variety of formsof which those of the external clampingtypea're quiteold in the art and satisfactory for some indicators and undersome circumstances. Su'c h external clamping devices,

however, are open to certain objections, particularly where the clamp piece is in an exposed position on the exterior of the indicator casing.

My present invention provides for bezel locks which may be of the built-in-type and so positioned and contained within the wall of the casing as to be protected thereby. Moreover, according to my invention I am able to do this without material addition of cost over the older external clamping locks.

As illustrative of my invention I have shown an indicator construction including such bezel lock together with certain modifications or variants of the same. These appear in the accompanying drawing as follows:-

Fig. 1 is a partly sectioned view of an indicator of a type in accordance with my invention.

Fig. 2 is a fragmentary view partly in section through the locking mechanism of such an indicator.

Fig. 3 is a fragmentary section of a modified form of lock, and I Fig. 4 is a section through the lock portion of a further modified form of indicator in accordance with my invention.

In this drawing I have shown an indicator construction in which the casing consists of a cylindrical shell I the exterior of which is uninterrupted save for the exterior opposite spindle bearings I0 and I I of the contact rod or feeler I3, the former being tightly closed by a dust cap I2.

Such a shell I is of sufficient thickness to be recessed or rabbeted as at I at its front and rear edges to receive aback plate 2 and a front plate 1 3. This plate 3 carries the bridge piece and the bearings for the internal parts and constitutes a front closure for the shell I.

Rotatably mounted on the front edge of the shell I is a knurled bezel ring 5 carrying the usual dial and transparent protective bezel. The inner face of the ring 5 is channeled as at I5 and so overlies the front edge of the casing I in the plane of the front plate 3.

The inner face of the casing I is transversely grooved as at I6 to receive a locking piece I4. At its outer end the piece I4 has an upturned foot I4 This footed end projects through an opening it in the edge of the front plate-3 and thus is properly held and guided.

The edge I of the casing I is'no'tchedas at I to receive the foot I4 and support'and guide it in its relation to "the channel I5 of "the bezel ring 5 for which it acts both as a lock and a keeper.

Such a lock is preferably controlled 'by a threaded clamping member. In "the form shown in Fig. 2 a headed stud 'II passes throughthe block it and the casing I being threaded at its outer portion to receive the bezel clamp nut I8. This may be loosened to free or unlock the bezel or tightened to draw up on the lock piece I4 and push the edge of its upturned foot'l4 radially outward against the bottom wall of the bezel groove I5and thus hold the bezel against rotation. As the footed lock piece I4 and the upturned foot I 4 are guided and supported in the notches I and 3 the foot acts as a broad steady keeper for holding the bezel ring 5 in its rotatable assembly on the edge of the casing I.

In the'modified form shown in Fig. 3, the parts are essentially the same but the lock piece 24 is tapped to receive the threaded end 2'! of a shouldered clamp screw 28 which draws up on the clamp and forces its footed end 24 against the bottom wall of the groove I5 of a bezel ring 5 as before described.

In both of these forms the exposed surface of the casing I is imperforate except for the clamp screw hole which is covered by the nut I8 (Fig. 2) or the head 28 (Fig. 3) so that there are no external channels, blocks, guide pins or other interruptions to the surface of the case I. This is of great advantage and in contrast to the modification shown in Fig. 4 in which the case I has its surface recessed as at 30 to receive a slidable clamp 34 having a short upturned foot 34 which is engaged in the groove of the bezel ring 5. The clamp 34 has a beveled opening 35 in which the beveled shoulder 38 of a screw 38 bears. As the threaded portion 3'? is screwed in or out the beveled shoulder 38 crowds the slide 35 in one direction or the other forcing the foot 34 against the side wall of the interior groove of a bezel ring 5.

By making the locking piece flush with the casing surface and with as close a fit as is consistent with its locking movement most of the objectionable features of the old outside locks are avoided and the qualities of the inside lock approximated.

I am aware that in the prior art it has been proposed to clamp a bezel ring by contact with its inner face. I am also aware that the old bezels usually had inner grooves for engagement by a screw, or stud or catch to hold the bezel in assembly and I do not therefore claim such broadly but I am not aware of any prior indicator in which an internal bezel look was provided to engage such a bezel inner groove and thus serve as both lock and keeper, or constructed and embodied in such an indicator combination as I have herein shown and described.

What I therefore claim and desire to secure by Letters Patent is:

1. In a dial gage, a cylindrical casing, a front plate and a back plate in the ends of said casing, a bezel rotatably mounted on the front edge of the casing cylinder and overlying the front plate, said bezel having an internal groove adjacent the casing edge, said casing and front plate having a transverse interior recess, a locking piece guided in said recess, threaded adjusting means for the locking piece disposed through the casing and having an operating portion externally thereof, said locking piece having at its end a clamping foot disposed through the casing edge and having its end within the bezel groove for radial outward contact with the groove bottom when the bezel is to be clamped in place.

2. In a dial gage, a, cylindrical casing, a front plate and a back plate in the ends of said casing, a bezel rotatably mounted on the front edge of the casing cylinder and overlying the front plate, said bezel having an internal groove adjacent the casing edge, said casing having a transverse interior recess and a, radial opening from said recess through the casing edge, a. locking piece guided in said recess, threaded adjusting means for the locking piece disposed through the casing and having an operating portion externally thereof, said front plate having an opening communicating with said slot, said locking piece having at its end a clamping foot disposed through said radial opening in the casing edge and having its end within the bezel groove for clamping contact with the groove bottom when the bezel is to be clamped in place.

3. In a dial gage, a cylindrical casing, a bezel rotatably mounted on the front edge of the casing cylinder, said bezel having an internal groove adjacent the casing edge, said casing having a transverse interior recess on its inner surface, a locking piece guided in said recess, threaded adjusting means for the locking piece disposed through the casing and having an operating portion externally thereof, said locking piece having at its end a clamping foot and having its end within the bezel groove for radial outward contact with the groove bottom when the bezel is to be clamped in place.

JAMES G. SISSON. 

